The present invention relates generally to circular knitting machines and, more particularly, to apparatus and methods for removing debris which accumulates during the course of machine operation in the cylinder slots of such machines, especially the needle and sinker rest ring slots of so-called sinker-top or single-needle circular knitting machines.
At substantially all stages of the processing of textile fibers, particularly cotton, from the initial fiber cleaning and preparation stage through yarn spinning and fabric production, the necessary handling of the textile fibers and yarns formed therefrom inherently liberates minute pieces of fiber, commonly referred to as lint, as well as other particulate dust and debris which tend to become readily airborne within the work area of the textile processing plant and ultimately to settle and accumulate on machinery and other exposed surfaces within the plant interior.
In fabric production operations, airborne lint and dust which settles on the processing machinery may adversely affect the proper operation of machinery components and may even cause machine stoppages as well as defects in the fabric being produced.
A variety of approaches have been taken in the past to control the accumulation of lint and other debris on textile machinery. For example, various equipment has been proposed and is available to continuously filter ambient debris-laden air within the working environment in a textile plant. Also, fans and other blower equipment may be mounted within the textile workplace, sometimes directly attached to the textile machinery itself, to generate moving forced air currents over machinery surfaces which are prone to debris accumulation and within other strategic areas of textile plants to minimize debris accumulation on machinery surfaces. Additionally, it is commonplace to provide machine operators with hand-held nozzles supplied with compressed air to perform selective cleaning of machine components on a periodic basis.
While generally effective on an overall basis, equipment and techniques of the type described may have little affect on debris accumulation on machine components which are difficult to reach or cannot be reached by such equipment. For example, textile circular knitting machines characteristically have a rotatable cylinder circumferentially formed with a plurality of axial slots each of which carries a reciprocating knitting needle. In many circular knitting machines commonly called sinker-top or single needle machines, an annular dial is fixed to the cylinder concentrically about its upper end for integral rotation therewith and is formed with a plurality of radial slots offset from the cylinder needle slots for carrying sinkers which reciprocate radially between the cylinder needles. A radially-slotted sinker rest ring is affixed to the upper end of the cylinder with its slots aligned with the dial slots to support the sinkers when projected from the dial radially between the cylinder needles. To a large extent, the cylinder needle slots are covered by cam plates and other machinery components so that the slots are not easily accessible for cleaning. Nevertheless, because the slots open upwardly for needle reciprocation in the normal course of machine operation, the slots are subject to accumulation of lint and debris released from the yarns being knitted as well as airborne lint and debris. Likewise, the knitted fabric produced by the interaction of the reciprocating needles and sinkers is withdrawn inwardly of the cylinder directly over the sinker rest ring, making its slots subject to accumulation of released lint and debris while at the same time covering the slots from ready access for cleaning. Such accumulations are of particular concern since they may impair the proper reciprocation and knitting action of the needles and sinkers.
One common technique to address this problem has been to periodically take circular knitting machines out of service, e.g., every few weeks of operation, for careful cleaning of the needle and sinker rest ring slots of the cylinder. Another approach has been for a machine operator to manually pour lubricating oil into the slots at the upper end of the cylinder upon each doffing of fabric from the machine to attempt to wash accumulated debris from the slots. However, this oiling technique is difficult to regulate and, moreover, because the knitted fabric covers the sinker rest ring slots, these slots generally are not penetrated well with oil and at the same time a significant portion of the fabric becomes soiled with oil and must be discarded. Some conventional machines are equipped with an oiling device which can be selectively operated by the machine operator to dispense a flow of oil into the cylinder slots to perform essentially the same washing operation. This oiling technique also is largely ineffective to loosen and remove any significant amount of accumulated debris and typically soils a significant amount of fabric with the lubricating oil. Since conventional wisdom is that this form of oiling operation should be performed upon each doffing of the knitting machine, substantial fabric losses are thereby suffered, and the efficiency of the machine's operation is correspondingly reduced.